Topic: Is Oil Consumption Typical of K1 Head?

[Finnigan]

Came across a K1 head from Kurt here in San Diego, the head was ported and something I couldn't pass up for my build.  I noted that the exhaust valves were the tapered non-seal version like the early sandcast heads.

With everything back together and 600 miles on the new motor I'm still noticing some white smoke in the exhaust.  Today I swapped exhaust systems and took a look at the exhaust ports and head had a little bit of oil coming from the exhaust valves, nothing crazy but I'm not used to seeing it.

Are these early valve guides known to let a little oil pass through?

[scottly]

Yes, my K1 puffs a little oil smoke every now and then, but overall oil consumption isn't that bad. I believe some of the smoke is caused when oil gets blown into the hot exhaust, as it doesn't show on the spark plugs.

[Finnigan]

Thanks for the info, my plugs are not oily at all.  Maybe I live with it until the next tear down

[HondaMan]

The tapered-tip valve guides are made from Stellite. They are hard as glass, and can wear the valve stems when those stems got rusty after the engine sat for a long time. So, I've found that replacing the valves, not the guides, is the correct fix for those. Many times. It is backward from the later engines, which, around the 3/72 builds of the K2 and later, became ordinary cast iron. On those later ones, it is the valve guides that wear and not the valve stems.

I would estimate that the head sat for a long time, got rusty valves, then got cleaned up and someone found those guides were still in spec (mine - early K2 - went over 125k miles before even beginning to show oil loss). Those Stellite guides are the cat's meow! The K1 has them on the intake side, too, so if they are ever pumping oil, look at the valve stems, full length. They will likely be worn nearest the intake port, letting the valve wiggle fore-and-aft in the head. New valves are also that fix, in most cases - not new guides.

[scottly]

Maybe I live with it until the next tear down

The last time I had mine torn down, I had two of the bronze exhaust valve guides replaced with new bronze guides, since I had noticed some smoke and they were the only ones showing wear. It still smoked on occasion, so I also thought I would live with it for the time being. That was 45 years ago, and it hasn't gotten any worse over the years.

[PeWe]

I have an old K1 head with those guides without seals.
I have a new set of 8 guides, 8 Honda valves + seals.  (Yamiya were out of stock of their probably better and lower priced set of guides.)

I have not got the thumb to leave it to my nearby shop.

It smoked some during start, too much for my taste.
Smoked even more while riding due to very optimistic combination of worn bores and stock sized CI pistons that need half that clearance as absolutely max.

A fresh restored head and cylinder wirh new pistons fixed that.
It takes very little oil. Last change was after 55000km. Oil felt still good. Spectro mineral 20W-50.

I had planned to change earlier but forgot.  Frank related rides

[MRieck]

Use the iron guides Yamiya sells.....they are Japanese and the best I have seen. The ID's hone perfectly and the OD's are very, very consistent. I cut a new c clip groove .080 above the existing one so it sits a bit lower in the head so larger cams can be used without the the keeper groove dipping under the seal. Use guide seals too.....Honda saw the light after a couple of years.

[PeWe]

..... keeper groove dipping under the seal.....

Done that, not fun. Engine transformed to an oil pump after a while. Oil disappeared quickly despite legal speeds. I checked the dip stick very frequently to not get red light during the fatal ride....
Keeper grooves could be shorter....
Clip groove was recut for deeper sitting guide but not enough.. Probably 315 cam as reference, not 125-75...

[MRieck]

..... keeper groove dipping under the seal.....

Done that, not fun. Engine transformed to an oil pump after a while. Oil disappeared quickly despite legal speeds. I checked the dip stick very frequently to not get red light during the fatal ride....
Keeper grooves could be shorter....
Clip groove was recut for deeper sitting guide but not enough.. Probably 315 cam as reference, not 125-75...

I believe that was one of the reasons Honda went to a more conventional keeper with the single bead.

[Finnigan]

The tapered-tip valve guides are made from Stellite. They are hard as glass, and can wear the valve stems when those stems got rusty after the engine sat for a long time. So, I've found that replacing the valves, not the guides, is the correct fix for those. Many times. It is backward from the later engines, which, around the 3/72 builds of the K2 and later, became ordinary cast iron. On those later ones, it is the valve guides that wear and not the valve stems.

I would estimate that the head sat for a long time, got rusty valves, then got cleaned up and someone found those guides were still in spec (mine - early K2 - went over 125k miles before even beginning to show oil loss). Those Stellite guides are the cat's meow! The K1 has them on the intake side, too, so if they are ever pumping oil, look at the valve stems, full length. They will likely be worn nearest the intake port, letting the valve wiggle fore-and-aft in the head. New valves are also that fix, in most cases - not new guides.

The bare head was all that was used, I had a good set of K6 valves and new APE springs.  The head had a full valve job done and I trust the person who did the work.  Just rubs me the wrong way that a new (and expensive) built engine smokes...

[HondaMan]

What oil is in it?

[Finnigan]

Motul 5100 15W50

[MRieck]

That's good oil. I put a mildly ported early head on my bike about 35 years ago...it had the tapered exhaust guides. It burned oil and people I rode with could see it and smell it. All that stopped when I went back to a later head with guide seals on the exhaust. No seals isn't a good idea....change those exhaust guides.

[HondaMan]

This all reminds me of the first K0 750K0 (not sandcast, I don't think) that our Peoria shop got to see inside the bores in the summer of 1970: the owner (and his friend on an H-D Sportster) had ridden hard and fast from IL to the Grand Canyon with typical 1970s full load: the Honda had a sleeping bag tied down over the instruments and he let the Sporty set the speed, reported to us to be 100 MPH give-or-take most of the way. The H-D didn't make it home, seized up in Nebraska on the way home. The 750 did, but limping: the rider reported he moved the sleeping bag to the back of the bike after the Canyon and with the sun on the idiot lights didn't see the OIL light flickering (at 100 MPH!) now and then until he sat up at one point. The bike had burned most of the oil (none showing on the dipstick). He stopped in the next town and "changed the oil" to more 10w40 Valvoline (his favorite) while his friend found a place to park his dead H-D. When the Honda came back to our shop some of the exhaust valves were burned and several intakes didn't seal any more. That was the first guide replacement job I remember being done on these bikes. Honda warranteed it, too! The bike only had around 3000 miles on it, pipes were covered with burned-on oil.

[Finnigan]

Went for a 60 mile ride the other day, bike ran great but I don't think I can tolerate the burning oil issue any longer.  Whenever I stopped at a light for more than 30 seconds I'd be surrounded by light white smoke.  Someone even rolled their window down to let me know by bike was smoking.

Had to happen might as well be now, time to pull the motor and get the head worked on.  Can I reuse all gaskets and washers from the last build (800 miles ago) including the MLS gasket if just the head is coming off?

[scottly]

Were the guides new? That much smoke sounds like maybe more than just a lack of seals on the exhaust guides. What else was done to the engine?

[Finnigan]

The guides were the original K1 seal-less valve guides.  I'll take a photo of the ports when the headers are off but there is oil coming past the exhaust valves.

[seanbarney41]

Yeah, you got something more wrong than just no exhaust seals on a K1.  Also, oil smoke should be blue.

[Finnigan]

Well, I'm not going to say its impossible something else is going on but I have seen oily residue in one of the old headers before I put my 4 into 1 on.

The ignition timing is advanced and there is ALWAYS white steam/smoke coming from the top cover breather.  Also the engine is consuming oil (about a quart in 800 miles).  Plugs are not oily so I assume this is happening at the exhaust based on the evidence I've seen.

[scottly]

there is ALWAYS white steam/smoke coming from the top cover breather.

You have something more than just guide seals going on. Have you done compression/leakdown tests?

[PeWe]

I have reused MLS gasket, used ca 1700km, just over 1000 miles.
No problem when the coating is intact.
I tightened it a little more next time just for sure.


Base gasket too if fiber and cylinder not lifted.

RCS base gasket reused several times. Last time a very thin layer of high temp RTV on its outer surfaces.

Important to use rigid heavy duty cylinder studs with MLS.
If not, it might leak oil into cylinders and cause heavy smoking. 21-22 ft lbs needed.

[Finnigan]

there is ALWAYS white steam/smoke coming from the top cover breather.

You have something more than just guide seals going on. Have you done compression/leakdown tests?

Yes on compression, no on leak down.  I don't trust the cheap-o gauge I have but all 4 cal are within 5 psi of each other

[Finnigan]

I have reused MLS gasket, used ca 1700km, just over 1000 miles.
No problem when the coating is intact.
I tightened it a little more next time just for sure.


Base gasket too if fiber and cylinder not lifted.

RCS base gasket reused several times. Last time a very thin layer of high temp RTV on its outer surfaces.

Important to use rigid heavy duty cylinder studs with MLS.
If not, it might leak oil into cylinders and cause heavy smoking. 21-22 ft lbs needed.

I've installed the heavy duty studs, in my notebook I wrote that I tightened them to 17 ft lbs... something to check for sure

[MRieck]

Go to 22lbs on the HD studs

[Finnigan]

Before I get to work taking parts off, quick video of the symptoms